GB2117713A

GB2117713A - A collapsible floating pontoon

Info

Publication number: GB2117713A
Application number: GB08210036A
Authority: GB
Inventors: Brockmann Heinrich; Gerhard Thieme
Original assignee: GOEPPNER KAISERSLAUTERN EISEN
Current assignee: GOEPPNER KAISERSLAUTERN EISEN
Priority date: 1982-04-05
Filing date: 1982-04-05
Publication date: 1983-10-19
Also published as: GB2117713B

Abstract

A floating bridge comprises collapsible floating pontoons which have four individual floating bodies (12) connected by means of articulations (12) and collapsible into a W-shape. To assist the folding -up and unfolding procedure, a cable- control device is provided consisting of cable controls and levers (9, 11). To take up temporary peaks in the load to which the cable controls (9) are exposed coil springs (14) are interposed in the cable controls. When a load limit is exceeded, these coil springs act as resilient extension means. It is not necessary for the cable controls to be oversized, dependent upon any possible peak loads. <IMAGE>

Description

SPECIFICATION Collapsible floating pontoon The invention relates to a collapsible floating pontoon which comprises four individual floating bodies which are connected by means of articulations, which are folded up into a Wshape and can be transported on a lorry thus arranged in conveying position. When unfolded and placed on water, the four parts form, after being appropriately locked, a substantially parallelepipedal pontoon. Pontoons of this type can be joined together in any number desired to form floating bridges or ferries.

When unfolding these four-part pontoons a crane may be used but when folding them up a crane has to be used, which engages on the articulation by which the two middle pontoons parts are interconnected at their lower longitudinal edge. When being unfolded, the buoyancy of the middle floating bodies opens them as soon as they are placed on water. The outer floating bodies are opened by a kinematic system, which substantially comprises cable controls and levers, depending on the opening angle of the middle floating bodies.

During folding-up, the outer pontoon parts are directed inwards by a push-boat, so that they are thus applied against the respective associated middle pontoon.

In particular when being folded-up, the rope or cable of the kinematic system is severely stressed by the force with which the pushboat acts on the outer pontoon, taking into account the leverages, in which case the angular ratios at the articulation point, determined by the hoisting by means of a crane, are also of significance.

In known pontoons of this type, such as disclosed for example in the reference work 'Militärtechnik' part 4, 1972, pages 182 and 183, in which a Soviet pontoon vehicle is described, or such as those evident from DE AS 1 784 593, very often tensile loading of the cable thus occurs, which exceeds its breaking strain and thus results in cable fracture. However, this overloading of the cable only occurs in a quite brief period during the entire cycle of the movements of the pontoon parts and only when the angular and force ratios are particular unfavourable.Accordingly, it does not appear to be a good idea to endeavour to solve the problem merely by a multiple oversizing of the cables, which in addition to increased weight results in a not inconsiderable increase in space requirement, thus leading to a substantial increase in space requirement precisely for the cable controls arranged at or in the side faces of the pontoon parts, which at the same time are end faces of the pontoon. Similarly, varying the lever lengths in the kinematic system also has the disadvantage that these levers then protrude beyond the contours of the pontoon parts and, therefore, are easily exposed to damage.

Accordingly, the invention is based on the object of finding ways and means, without otherwise pointless oversizing and without parts readily exposed to damage, of enabling the kinematic system to be designed so that any temporary load peaks which may occur can be taken up without cable fracture.

The invention achieves this object with a collapsible floating pontoon comprising four individual floating bodies connected by means of articulations and collapsible into a W-shape in the conveying position, having a kinematic system consisting of cable controls and levers for assisting the folding-up and unfolding procedure in such a way that, for relieving the cables of stress upon briefly exceeding the maximum permissible load of the cables during the folding-up and unfolding procedure, coil springs are interposed in the cable controis as resilient extension means which become operative when a load limit is exceeded.

These coil springs have such a spring characteristic that the cable force is not greater than the spring tension set according to the weight of the outer pontoon.

Further features of the invention and details of the advantages achieved thereby will be apparent from the following description of one embodiment of the subject-matter of the invention illustrated merely diagrammatically and by way of example in the accompanying drawings.

Figure 1 shows a partial view of a pontoon in a condition in which, for example, the two middle pontoon parts (e.g. during folding-up) form an angle of about 90 ; and Figure 2 illustrates the means for preventing cable fracture, in the form of a coil spring.

The parts 1, 2 and 3 of a pontoon are shown in front view in Fig. 1 in a halfunfolded condition. The pontoon part 3 is cutaway and continues to the right in the same manner as the pontoon part 2 to the left. A further pontoon part corresponding to the pontoon part 1 is articulated thereto. The relationships between the pontoon parts 3 and the not-visible pontoon part are the same as those between the pontoon parts 1 and 2.

The pontoon is folded together upright. For this purpose, a push-boat 4 is employed, by means of which the pontoon part 1 is pushed against the pontoon part 2, both folding one against the other. A hoisting implement 6 of a crane 7 (indicated in chain lines) engages in the articulation zone 5 between the two pontoon parts 2 and 3.

In the articulated zone 5 is provided a double lever 8, at the free ends of which are applied pull cables 9 and 10 which at their other ends are articulated to levers 11 of the outer pontoon parts 1 in the articulation zone 12 between the pontoon parts 1 and 2.

As a result of the pulling force of the hoisting implement 6 of the crane 7 acting upwards in the direction of arrow 1 3 and as a result of the pushing force of the push-boat 4, the pontoon is folded together until the four pontoon parts, parallel and side by side, occupy a vertical position adjoining one another.

During the folding-up procedure, as also during unfolding, tensile forces occur in the pull cables 9 and 10 of the kinematic system consisting of these cables and of the levers 8 and 11, which tensile forces could overload the cables, possibly in short zones of the movement cycle, to such an extent that they break.

In order to obviate this, in accordance with the invention coil springs 14 are provided in the cables for temporarily lengthening the cable under resilient restoring force. These coil springs 14 are merely indicated schematically in Fig. 1 and are illustrated in their form of embodiment in detail in Fig. 2. If the breaking strain limit of the cable is temporarily exceeded, these springs 14 take up the forces exceeding this limit under equally temporary elongation. Once the overloading condition has passed, the springs return to their original position.

The lever 11 is designed as a two-armed lever with arms 1 5 and 16, is articulated at 1 7 to the pontoon part 1 and is supported by its arm 16 at 18.

Claims

1. A collapsible floating pontoon comprising four individual floating bodies connected by means of articulations and collapsible into a W-shape in the conveying position, having a kinematic system consisting of cable controls and levers for assisting the folding-up and unfolding procedure, wherein to relieve the cables of stress, when the maximum permissible load of the cables is briefly exceeded during the folding-up and unfolding procedure, coil springs are interposed in the cable controls as resilient extension means which become operative when a load limit is exceeded.

2. A collapsible floating pontoon substantially as herein described with reference to and as shown in the accompanying drawings.